All known water distillers prior to the present invention comprise a closed vaporization chamber, a heating element located near the chamber bottom, a steam outlet located near the top of the chamber and leading to a usually finned condenser coil, a venting outlet and a fan which blows fresh air over the condenser surface. The vaporization chamber is usually removable so that it may be filled with raw water and to provide the removal of residues and sediments.
The aforementioned parts of known water distillers are prone to repeated problems which are generally recognized in the distillation industry. Attempts to deal with these problems are discussed in the patent literature. For example, prior art distillation apparatuses provide generally horizontal heating elements and do not provide for the immersion of the heating element when the heating element is de-energized. Upon de-energizing, the residual heat in the heating elements of these prior art apparatuses quickly evaporates the remaining raw water supply. Under such conditions, the heating element can easily overheat, producing smoke and possibly causing a fire. Moreover, users do not always seat prior art distillation apparatuses on a perfectly horizontal plane. In such cases, inclinations of only 2 degrees may lead to the rapid overheating of the heating elements, which as described above, may produce smoke and possibly cause a fire.
U.S. Pat. No. 4,818,344 to Glucksman discloses a portable water distiller having a vaporization chamber containing a horizontally oriented electric coil heating element, a condenser coil and an electric fan motor for cooling the condenser coils outer surface. The receptacle of the portable water distiller to Glucksman is automatically kept full with water up to a predetermined level and is readily removable from the distiller for cleaning the residue. However, there exists no means to prevent the residual heat in the heating elements from quickly evaporating the raw water supply in the receptacle. Moreover, if a user were to incline such a distiller more than 2 degrees, leaving part of the heating element exposed and not surrounded by raw water, this would lead to a rapid temperature increase, which would result in the aforementioned smoke and/or fire conditions.
Another type of distilling apparatus is disclosed in U.S. Pat. No. 4,342,623 to Loeffier. This invention is portable and has an insulated container for raw water and a removable cover for the container and, includes a low-pressure seal which engages the container wall. A condenser coil is provided in the cover, along with a motor driven fan; an inlet and outlet ports which are provided about the periphery of the cover to allow cooling air to be drawn into the cover over the condenser coil and motor. An inlet tube connected to the condenser coil receives steam generated by a heater connected to the container bottom. It is evident that dismantling and reassembling the unit for cleaning purposes--a task to be done at least once a week--is quite formidable.
A further type of water distiller is disclosed in U.S. Pat. No. 4,339,307 to Ellis, which comprises a boiler compartment and a water-filled condenser compartment, combined in one shell, but separated by a partition wall. A condenser coil is disposed in the condenser compartment, and the steam passing there through is condensed by the raw water in the upper compartment. A drain valve is provided in the boiler compartment, which serves to purge impurities collected in the boiler. The water level in the boiler is controlled by a float valve which admits raw water from the condenser compartment, the latter having a similar float valve serving to control its water level. However, there exists no means for cleaning the bottom of the boiler, and it is evident that sediment will accumulate both in the boiler container and on the electrical emersion heater. These elements can, therefore, only be removed by complete dismantling of the water distiller.
The primary drawbacks of these embodiments is that in order to clean the boiler, the evaporation space and the electric heater, if possible, it is necessary to completely disassemble the apparatus. Moreover, a further drawback of these embodiments is that there exists no mechanism to prevent the residual heat in the heating element from quickly evaporating the raw water supply.